import { useCallback, useEffect, useState } from "react";
import { Link, useSearchParams } from "react-router-dom";
import { PageHeader } from "../components/layout/PageHeader";
import { OpportunityInboxCard } from "../components/radar/OpportunityInboxCard";
import { OpportunityDetailDrawer } from "../components/radar/OpportunityDetailDrawer";
import { Button, EmptyState, Select } from "../components/ui";
import { useRepos } from "../data/DataContext";
import type { Brand, BrandProduct, Opportunity, OpportunityRemovalReason, OpportunityReviewState, OpportunityTimeScope } from "../domain/types";
import { useFormatApiError } from "../lib/apiErrors";
import "../styles/radar.css";

const PAGE_SIZE = 20;

function normalizeSort(value: string | null): string {
  if (value === "posted") return "newest";
  if (value === "score") return "recommended";
  return value || "recommended";
}

export function RadarOpportunitiesPage() {
  const repos = useRepos();
  const formatError = useFormatApiError();
  const [params, setParams] = useSearchParams();
  const [list, setList] = useState<Opportunity[]>([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(() => Math.max(1, Number(params.get("page")) || 1));
  const [band, setBand] = useState(params.get("band") || "");
  const [state, setState] = useState(params.get("match_state") || "");
  const [brandId, setBrandId] = useState(params.get("brand_id") || "");
  const [productId, setProductId] = useState(params.get("product_id") || "");
  const [sort, setSort] = useState(() => normalizeSort(params.get("sort")));
  const [reviewState, setReviewState] = useState<OpportunityReviewState>((params.get("review_state") as OpportunityReviewState) || "pending");
  const [timeScope, setTimeScope] = useState<OpportunityTimeScope>((params.get("time_scope") as OpportunityTimeScope) || "today");
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState("");
  const [notice, setNotice] = useState<{ text: string; contactId?: string } | null>(null);
  const [brands, setBrands] = useState<Brand[]>([]);
  const [products, setProducts] = useState<BrandProduct[]>([]);
  const [selected, setSelected] = useState<Opportunity | null>(null);
  const [busyId, setBusyId] = useState<string | null>(null);
  const [advancedOpen, setAdvancedOpen] = useState(() => Boolean(params.get("band") || params.get("match_state") || params.get("brand_id") || params.get("product_id")));
  const scout = (repos as unknown as { scout?: { listBrands: () => Promise<Brand[]>; listProducts: (id: string) => Promise<BrandProduct[]> } }).scout;

  useEffect(() => {
    if (scout) void scout.listBrands().then(setBrands).catch(() => setBrands([]));
  }, [scout]);

  useEffect(() => {
    if (!scout || !brandId) {
      setProducts([]);
      return;
    }
    void scout.listProducts(brandId).then(setProducts).catch(() => setProducts([]));
  }, [scout, brandId]);

  const load = useCallback(async () => {
    setLoading(true);
    try {
      const result = await repos.radar.listOpportunities({
        page,
        pageSize: PAGE_SIZE,
        band: band || undefined,
        match_state: state || undefined,
        brand_id: brandId || undefined,
        product_id: productId || undefined,
        review_state: reviewState,
        time_scope: timeScope,
        sort,
      });
      setList(result.list);
      setTotal(result.total);
      setError("");
    } catch (e) {
      setError(formatError(e));
    } finally {
      setLoading(false);
    }
  }, [repos.radar, page, band, state, brandId, productId, sort, reviewState, timeScope, formatError]);

  useEffect(() => { void load(); }, [load]);

  async function updateReviewState(
    opportunity: Opportunity,
    patch: { state: OpportunityReviewState; removal_reason?: OpportunityRemovalReason; removal_note?: string },
    successText: string,
  ) {
    setBusyId(opportunity.id);
    setNotice(null);
    try {
      const updated = await repos.radar.updateOpportunityReviewState(opportunity.id, patch);
      setSelected((current) => current?.id === updated.id ? null : current);
      await load();
      setError("");
      setNotice({ text: successText });
    } catch (e) {
      setError(formatError(e));
    } finally {
      setBusyId(null);
    }
  }

  async function acceptOpportunity(opportunity: Opportunity) {
    setBusyId(opportunity.id);
    setNotice(null);
    try {
      const result = await repos.radar.acceptOpportunity(opportunity.id);
      setSelected((current) => current?.id === opportunity.id ? null : current);
      await load();
      setError("");
      setNotice({
        text: "已加入名單並移到已處理。接下來可到名單安排追蹤、備註或回報成交。",
        contactId: result.contact_id,
      });
    } catch (e) {
      setError(formatError(e));
    } finally {
      setBusyId(null);
    }
  }

  function writeParams(changes: Record<string, string>) {
    const next = new URLSearchParams(params);
    for (const [name, value] of Object.entries(changes)) {
      if (value) next.set(name, value);
      else next.delete(name);
    }
    setParams(next, { replace: true });
  }

  function resetFilters() {
    setBand("");
    setState("");
    setBrandId("");
    setProductId("");
    setSort("recommended");
    setTimeScope("today");
    setAdvancedOpen(false);
    setPage(1);
    const next = new URLSearchParams();
    next.set("review_state", reviewState);
    next.set("time_scope", "today");
    setParams(next, { replace: true });
  }

  const advancedFilterCount = [band, state, brandId, productId].filter(Boolean).length;
  const filtered = Boolean(advancedFilterCount || sort !== "recommended" || timeScope !== "today");
  const pageCount = Math.max(1, Math.ceil(total / PAGE_SIZE));

  return (
    <>
      <PageHeader title="商機收件匣" />

      <section className="hb-radar-intro">
        <div>
          <strong>每張商機只要做一個決定</strong>
          <p>值得繼續接觸就加入名單；已自行看完就標示已處理；不是你的客戶就標示不適合。這些整理動作都不扣點。</p>
        </div>
        <nav className="hb-radar-intro__actions" aria-label="商機結果導覽">
          <Link className="hb-btn hb-btn--ghost" to="/app/radar/watches">管理巡邏</Link>
        </nav>
      </section>

      <ol className="hb-inbox-decision-guide" aria-label="商機收件匣操作方式">
        <li><span>1</span><div><strong>先看需求</strong><small>閱讀原文與「為什麼推薦」。</small></div></li>
        <li><span>2</span><div><strong>值得跟進</strong><small>加入名單，後續做備註與追蹤。</small></div></li>
        <li><span>3</span><div><strong>不需要跟進</strong><small>只標示已處理，或選原因標示不適合。</small></div></li>
      </ol>

      <section className="hb-radar-filter-panel" aria-label="篩選商機收件匣">
        <div className="hb-radar-filter-panel__head">
          <div className="hb-radar-inbox-tabs" role="tablist" aria-label="商機工作狀態">
            {(["pending", "completed", "removed"] as OpportunityReviewState[]).map((value) => (
              <Button key={value} type="button" variant={reviewState === value ? "primary" : "ghost"} aria-pressed={reviewState === value} onClick={() => {
                setReviewState(value); setPage(1); writeParams({ review_state: value, page: "" });
              }}>
                {value === "pending" ? "待決定" : value === "completed" ? "已處理" : "已移除"}
              </Button>
            ))}
            <span>共 {total} 筆</span>
          </div>
          {filtered ? <Button type="button" variant="ghost" onClick={resetFilters}>清除篩選</Button> : <span>預設先顯示最值得跟進的結果</span>}
        </div>
        <div className="hb-radar-inbox-essential-filters">
          <Select name="all-time-scope" label="看哪段時間" value={timeScope} onChange={(e) => {
            const value = e.target.value as OpportunityTimeScope;
            setTimeScope(value); setPage(1); writeParams({ time_scope: value, page: "" });
          }}>
            <option value="today">今天</option><option value="7d">近 7 天</option><option value="all">全部</option>
          </Select>
          <Select name="all-sort" label="先看哪些" value={sort} onChange={(e) => {
            setSort(e.target.value); setPage(1); writeParams({ sort: e.target.value === "recommended" ? "" : e.target.value, page: "" });
          }}>
            <option value="recommended">最值得跟進</option><option value="newest">最新貼文</option><option value="oldest">最舊貼文</option><option value="product_fit">最符合產品</option><option value="demand_intent">需求最明確</option>
          </Select>
          <Button type="button" variant="ghost" aria-expanded={advancedOpen} onClick={() => setAdvancedOpen((value) => !value)}>
            {advancedOpen ? "收起更多篩選" : `更多篩選${advancedFilterCount ? `（${advancedFilterCount}）` : ""}`}
          </Button>
        </div>
        {advancedOpen ? <div className="hb-radar-filter-grid hb-radar-filter-grid--all" aria-label="更多篩選">
          {brands.length ? (
            <Select name="all-brand" label="品牌" value={brandId} onChange={(e) => {
              const value = e.target.value;
              setBrandId(value); setProductId(""); setPage(1);
              writeParams({ brand_id: value, product_id: "", page: "" });
            }}>
              <option value="">全部品牌</option>
              {brands.map((b) => <option key={b.id} value={b.id}>{b.display_name}</option>)}
            </Select>
          ) : null}
          {products.length ? (
            <Select name="all-product" label="產品" value={productId} onChange={(e) => {
              setProductId(e.target.value); setPage(1);
              writeParams({ product_id: e.target.value, page: "" });
            }}>
              <option value="">全部產品</option>
              {products.map((p) => <option key={p.id} value={p.id}>{p.label}</option>)}
            </Select>
          ) : null}
          <Select name="all-band" label="商機意向" value={band} onChange={(e) => {
            setBand(e.target.value); setPage(1); writeParams({ band: e.target.value, page: "" });
          }}>
            <option value="">全部意向</option><option value="high">高意向</option><option value="mid">中意向</option><option value="low">低意向</option>
          </Select>
          <Select name="all-state" label="產品匹配" value={state} onChange={(e) => {
            setState(e.target.value); setPage(1); writeParams({ match_state: e.target.value, page: "" });
          }}>
            <option value="">全部狀態</option><option value="eligible">可跟進</option><option value="weak">弱適配</option><option value="excluded">已排除</option><option value="generic">未指定產品</option><option value="stale">超過 14 天</option>
          </Select>
        </div> : null}
      </section>

      {error ? <p className="hb-banner-error" role="alert">{error}</p> : null}
      {notice ? <div className="hb-banner-ok" role="status"><span>{notice.text}</span>{notice.contactId ? <Link to={`/app/crm?contact=${encodeURIComponent(notice.contactId)}`}>現在前往名單</Link> : null}</div> : null}
      {loading ? <p className="hb-radar-section__hint" role="status">正在整理商機結果…</p> : null}
      {!loading && !error && !list.length ? (
        <EmptyState
          title={reviewState === "pending" ? "目前沒有待決定的商機" : reviewState === "completed" ? "目前沒有已處理的商機" : "目前沒有已移除的商機"}
          description={filtered ? "清除篩選或改看其他時間範圍。" : reviewState === "pending" ? "等待下一輪巡邏，或先建立產品巡邏。" : "切換到「待決定」繼續處理商機。"}
          action={filtered ? <Button type="button" variant="ghost" onClick={resetFilters}>清除篩選</Button> : reviewState === "pending" ? <Link className="hb-btn hb-btn--secondary" to="/app/radar/watches">管理巡邏</Link> : undefined}
        />
      ) : null}

      {!error ? (
        <section className="hb-radar-page hb-radar-all-results">
          {list.map((o) => <OpportunityInboxCard
            key={o.id}
            opportunity={o}
            busy={busyId === o.id}
            onOpen={setSelected}
            onAccept={(item) => void acceptOpportunity(item)}
            onComplete={(item) => void updateReviewState(item, { state: "completed" }, "已標示為已處理；沒有建立聯絡人名單。")}
            onRemove={(item, input) => void updateReviewState(item, { state: "removed", removal_reason: input.reason, removal_note: input.note }, "已標示為不適合，可從「已移除」還原。")}
            onRestore={(item) => void updateReviewState(item, { state: item.previous_review_state === "completed" ? "completed" : "pending" }, "已還原商機。")}
          />)}
          {total > PAGE_SIZE ? (
            <div className="hb-radar-pager">
              <Button variant="ghost" disabled={page <= 1} onClick={() => { const next = page - 1; setPage(next); writeParams({ page: String(next) }); }}>上一頁</Button>
              <span>第 {page} 頁／共 {pageCount} 頁</span>
              <Button variant="ghost" disabled={page >= pageCount} onClick={() => { const next = page + 1; setPage(next); writeParams({ page: String(next) }); }}>下一頁</Button>
            </div>
          ) : null}
        </section>
      ) : null}
      {selected ? <OpportunityDetailDrawer
        opportunity={selected}
        busy={busyId === selected.id}
        onClose={() => setSelected(null)}
        onAccept={(item) => void acceptOpportunity(item)}
        onComplete={(item) => void updateReviewState(item, { state: "completed" }, "已標示為已處理；沒有建立聯絡人名單。")}
      /> : null}
    </>
  );
}